Icing Physics Studies Using the 3D SIDRM Test Article: 2023 Icing Tests Analysis

In-flight icing is an important safety issue and is a factor that affects aircraft design and performance. Newer regulations are driving a need for improvements in airframe and engine icing simulation capability. Experimental data are required for the development of icing physics models and simulation validation. To that end, NASA conducted a series of component level icing physics tests at the NASA Icing Research Tunnel (IRT) in 2022 and 2023 that studied both supercooled liquid and ice-crystal icing. The test article that was utilized replicated 3D geometrical features of an inter-compressor duct and strut region of a turbofan engine. The surfaces of the Simulated Inter-compressor Duct Research Model (SIDRM) can be heated to simulate the warm surfaces of the turbofan inter-compressor duct. The test article was instrumented with pressure taps, heaters, heat flux gauges, and thermocouples, while 3D laser scans, photographs, video, and ice mass measurements were utilized to characterize the icing behavior. The 2023 tests utilized modified struts, which were larger compared to the tests conducted in 2022. There were multiple objectives for the 2023 test entry. The primary aim of these tests was to generate ice accretions on the SIDRM test article under well-characterized icing conditions. The ice accretion tests explored different test conditions to measure that parameter’s impact on ice accretion size, location, and characteristics (quality, shedding behavior, and physical attributes) under supercooled liquid and ice crystal clouds. Also, aerodynamic tests were conducted to characterize the flow field. Finally, icing threshold tests were performed to determine heat flux settings that differentiated between icing and running wet conditions for both supercooled liquid and ice crystal clouds. This report presents analysis of data collected from tests conducted in 2023, with comparison to 2022 data where applicable, and discusses the impact of the modified struts. The icing measurements collected during the SIDRM tests will be used to develop and validate 3D computational engine icing tools, such as GlennICE, that predictively assesses the onset and growth of ice. One of the goals of the sponsoring NASA project is to develop simulation models and tools that can assist in the design and certification of engines for flight in icing conditions in a cost‑effective way.